What is milk solid?

Milk is approximately 87 percent water and 13 percent solids. As it comes from the cow, the solids portion of milk contains approximately 3.7 percent fat and 9 percent solids-not-fat.

Milk fat carries the fat soluble vitamins A, D, E, and K. The solids-not-fat portion consists of protein (primarily casein and lactalbumin), carbohydrates (primarily lactose), and minerals (including calcium and phosphorus).

Solids-not-fat (SNF): proteins, lactose, minerals, acids, enzymes, vitamins. It is the total solids content minus the fat content.

Total Milk Solids: fat + SNF

The composition of milk is subject to changes due to numerous factors such as race, environmental conditions and health status of the mammary gland. Fat and protein are the components that tend to suffer greatest variations in milk even when in the same environmental conditions, and these variations are generally related to the nutrition and diet of animals.

Milk with high solids-not-fat is valuable to the consumer for its flavor and nutritional value and to the manufacturer of milk products, especially relating to cheese yield. Protein is the most important component of milk because of its nutritional value and its functional properties.
What is milk solid?